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Diffstat (limited to 'arch/unicore32/include/asm/delay.h')
| -rw-r--r-- | arch/unicore32/include/asm/delay.h | 52 |
1 files changed, 52 insertions, 0 deletions
diff --git a/arch/unicore32/include/asm/delay.h b/arch/unicore32/include/asm/delay.h new file mode 100644 index 00000000..164ae61c --- /dev/null +++ b/arch/unicore32/include/asm/delay.h @@ -0,0 +1,52 @@ +/* + * linux/arch/unicore32/include/asm/delay.h + * + * Code specific to PKUnity SoC and UniCore ISA + * + * Copyright (C) 2001-2010 GUAN Xue-tao + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * Delay routines, using a pre-computed "loops_per_second" value. + */ +#ifndef __UNICORE_DELAY_H__ +#define __UNICORE_DELAY_H__ + +#include <asm/param.h> /* HZ */ + +extern void __delay(int loops); + +/* + * This function intentionally does not exist; if you see references to + * it, it means that you're calling udelay() with an out of range value. + * + * With currently imposed limits, this means that we support a max delay + * of 2000us. Further limits: HZ<=1000 and bogomips<=3355 + */ +extern void __bad_udelay(void); + +/* + * division by multiplication: you don't have to worry about + * loss of precision. + * + * Use only for very small delays ( < 1 msec). Should probably use a + * lookup table, really, as the multiplications take much too long with + * short delays. This is a "reasonable" implementation, though (and the + * first constant multiplications gets optimized away if the delay is + * a constant) + */ +extern void __udelay(unsigned long usecs); +extern void __const_udelay(unsigned long); + +#define MAX_UDELAY_MS 2 + +#define udelay(n) \ + (__builtin_constant_p(n) ? \ + ((n) > (MAX_UDELAY_MS * 1000) ? __bad_udelay() : \ + __const_udelay((n) * ((2199023U*HZ)>>11))) : \ + __udelay(n)) + +#endif /* __UNICORE_DELAY_H__ */ + |